Post-synthesis of MSE-type titanosilicates by interzeolite transformation for selective anisole hydroxylation

Abstract

The practical application of MSE-type titanosilicate (Ti-MSE) catalysts in liquid-phase oxidation processes is facing the problem of inefficient and complex synthesis. A novel and efficient strategy is developed to post-synthesize...

Promoting Syngas to Olefins with Isolated Internal Silanols‐Enriched Al‐IDM‐1 Aluminosilicate Nanosheets

“…The bands at 3604 and 3660 cm À 1 were attributed to the acidic bridging hydroxyl Si(OH)Al and extra-framework Al-related hydroxyl (AlOH) respectively, [21] while the intensive bands at 3690-3750 cm À 1 were attributed to the SiOH groups. [22][23][24] The sharp band at 3724 cm À 1 in the Al-IDM-1 samples with Si/Al ratios > 100 was closely related to the non-fully connected internal Si atoms bearing OH groups, that is isolated internal SiOH groups in À ION structure viewed along the a-axis (Figure 2A, insert). The band became broadened when the Si/Al ratio decreased to � 100, which was possibly caused by delocalization interaction between bridging Si(OH)Al and internal SiOH groups, resulting in nonlocalized and non-equivalent chemical environment of internal SiOH groups.…”

“…The FTIR spectra of Al‐IDM‐1 samples in the hydroxyl‐stretching region were further collected (Figure 2A). The bands at 3604 and 3660 cm −1 were attributed to the acidic bridging hydroxyl Si(OH)Al and extra‐framework Al‐related hydroxyl (AlOH) respectively, [21] while the intensive bands at 3690–3750 cm −1 were attributed to the SiOH groups [22–24] . The sharp band at 3724 cm −1 in the Al‐IDM‐1 samples with Si/Al ratios >100 was closely related to the non‐fully connected internal Si atoms bearing OH groups, that is isolated internal SiOH groups in − ION structure viewed along the a ‐axis (Figure 2A, insert).…”

Seed-Assisted Interzeolite Conversion Strategy for Fabricating Lewis Acid Sn-CHA Zeolites

“…This strategy has been adopted by several groups in their efforts to achieve IZC. Wu et al accomplished the rapid synthesis of MSE by employing the IZC strategy, for which the addition of MSE seeds is indispensable . In Xiao’s study for probing the mechanism of IZC from Si–Al FAU to CHA, CHA seeds were added to facilitate structural transformation .…”

“…Wu et al accomplished the rapid synthesis of MSE by employing the IZC strategy, for which the addition of MSE seeds is indispensable. 22 In Xiao's study for probing the mechanism of IZC from Si−Al FAU to CHA, CHA seeds were added to facilitate structural transformation. 23 Moreover, in recent reports for advancing high Si-CHA zeolite preparation, they all took advantage of the seeding effect, such as providing the crystallization interface, reducing the particle size, shortening the induction period, and directing certain structures.…”